One way, Two way and One time bindings using SilverLight

This article will talk about three ways of binding object properties with SilverLight user interfaces. We will first go through the fundamentals of the 3 bindings and then take up a small sample which will demonstrate how the binding works. We have also attached the source for the same.

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As the name so the behavior. In one way bindings data flows only from object to UI and not vice-versa. For instance you can have a textbox called as 'TxtYear' which is binded with an object having property 'Year'. So when the object value changes it will be reflected on the silverlight UI, but the UI cannot update the year property in the object.

It is a three step procedure to implement one way binding. First create your class which you want to bind with the silverlight UI. For instance below is a simple class called as 'ClsDate' with a 'Year' property.

In the second step you need to tie up the 'Year' property with a silver light UI text box. To bind the property you need to specify 'Binding Path=Year' in the text property of the text box UI object. 'Year' is the property which we are binding with the text box UI object.

The final step is to bind the text box data context with the date object just created.

Two way binding ensure data synchronization of data between UI and Objects. So any change in object is reflected to the UI and any change in UI is reflected in the object.

To implement two way binding there are two extra steps with addition to the steps provided for 'OneWay'. The first change is we need to specify the mode as 'TwoWay' as shown in the below XAML code snippet.

Second change is we need to implement 'INotifyPropertyChanged' interface. Below is the class which shows how to implement the 'INotifyPropertyChanged' interface. Please note you need to import 'System.ComponentModel' namespace.

In one time binding data flows from object to the UI only once. There is no tracking mechanism to update data on either side. One time binding has marked performance improvement as compared to the previous two bindings discussed. This binding is a good choice for reports where the data is loaded only once and viewed.

Finally we have also binded the SilverLight UI objects with the class properties. Below is the XAML snippet for the same. One point to be noted is that 'Age' is bounded using two way mode as we need to modify the same from the user interface.